Getting Started 9
8300GETM.DOC TI-83 international English Bob Fedorisko Revised: 02/19/01 11:06 AM Printed: 02/19/01 11:06
AM Page 9 of 18
Take a 20 cm. × 25 cm. sheet of paper and cut X × X squares from two corners.
Cut X × 12.5 cm. rectangles from the other two corners as shown in the
diagram below. Fold the paper into a box with a lid. What value of X would
give your box the maximum volume V? Use the table and graphs to determine
the solution.
Begin by defining a function that describes the
volume of the box.
From the diagram: 2X + A = 20
2X + 2B = 25
V = A B X
Substituting:
V = (20
N
2X) (25
à
2
N
X) X
1. Press
o
to display the
Y=
editor, which is
where you define functions for tables and
graphing.
2. Press
£
20
¹
2
„
¤
£
25
¥
2
¹
„
¤
„
Í
to define the
volume function as
Y
1
in terms of
X
.
„
lets you enter
X
quickly, without
having to press
ƒ
. The highlighted
=
sign indicates that
Y
1
is selected.
Defining a Function: Box with Lid
20
A
X
X B X B
25
